Prototype drivers finished:
They're really poorly made, and they'll probably work
for about five seconds before messing up. There weren't any big problems,
just little annoyances and difficulties (i.e. cutting metal/plastic
and keeping it flat....getting the resistive coating to stick...knowing
how to tape mylar to the frame so it doesn't come off when I'm not
That said, I do know the associated problems now, and the next sets
I make will be nicer. I do need to figure out a better way to cut the
aluminum though. It would be great if the mini-hacksaw in the lab had
a blade. Maybe I'll go get one.
Notes on drivers: plastic spacers used were peoples' old credit cards,
giftcards, and ID cards. Perfect size! But the Stanford IDs actually
have a copper wire running behind the magnetic stripe. Weird.
I also cut the stators to be a little larger than the spacers to make
sure the more-uneven edges didn't affect the spacing, but only after
I finished did I realize that that would create problems with biasing
Resistive coating on the mylar is hand soap (which I heard was easier
to do than graphite). I originally tried dissolving Ivory soap (flakes
left over from a Kimball soap-carving event) but that didn't cover
with enough density. Now that I think of it, I may or may not have
disposed of the huge bag of soap. I ended up using the weird Airkem
stuff from the bathroom. It seems to work, but never really dries.
Err...I think I'll stick with graphite next time.
~I will take pictures next time I make drivers.